science notes Archives - Page 17 of 32 - Free ZIMSEC & Cambridge Revision Notes

Pest control

By garikaib|2025-02-12T09:06:11+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Tomato plant with red mite. Image credit thedemogadern.org ZIMSEC O Level Combined Notes: Pest Control

Pests cause damage to plants and spread diseases.
This results in a reduction in crop yields.
Control measures can be taken to minimise this damage.
The control measures can be either […]

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Exhaled air vs inhaled air

By garikaib|2025-02-12T09:42:06+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Air sacs. Image credit MediaWiki ZIMSEC O Level Combined Science Notes:Exhaled air vs inhaled air

Air which enters the lungs (inhaled air) is different in several regards to air that is passed out (exhaled air)
Exhaled air contains less oxygen and more carbon dioxide.
It is also warmer […]

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Investigating water loss in plants

By garikaib|2025-02-12T09:15:44+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Transpiration occurs mainly through the leaves. Image credit desk7.net ZIMSEC O Level Combined Science Notes: Investigating water loss in plants

Aim: To determine how plants loose their water

Materials: plants or branches from plants, weighing balance, containers, water, oil/Vaseline.

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Science: Ecosystems

By garikaib|2025-02-12T09:38:28+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

An ecosystem diagram. Image credit ck12.org ZIMSEC O Level Combined Science Notes: Ecosystems

Is a self-contained system of interdependent organisms and their physical environment
An ecosystem can also be defined as a biological community of interacting organisms and their physical environment.
In an ecosystem a community of living […]

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The Carbon cycle

By garikaib|2025-02-12T09:02:20+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The carbon cycle. Image credit windows2universe.org ZIMSEC O Level Combined Science Notes: The Carbon cycle

Carbon dioxide in the atmosphere is the source of carbon in ecosystems
Plants remove carbon dioxide from the air during photosynthesis and use it to build food compounds
Animals obtain the carbon […]

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Experiment: to show the cooling effect of methylated spirits

By garikaib|2025-02-12T09:13:32+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A bottle of methylated spirit. Image credit wilko.com ZIMSEC O Level Combined Science Notes: Experiment: to show the cooling effect of methylated spirits

Material: cotton wool,methylated spirits

Method

Dip a small piece of cotton wool into the methylated spirits
Rub some of […]

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Heating metals in air
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Heating metals in air

Notes, O Level Science Notes, Ordinary Level Notes

Heating metals in air

By garikaib|2025-02-12T09:32:08+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Heating metals in air

Some metals react with oxygen in the air at ordinary (room) temperature
Others only react with oxygen if they are heated in air
They may do this readily and release large amounts of energy in the process
Some metals hardily react at all even at very high temperatures

[…]

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Introduction to acids
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Introduction to acids

Notes, O Level Science Notes, Ordinary Level Notes

Introduction to acids

By garikaib|2025-02-12T08:59:45+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Introduction to acids

A lot of everyday materials are acidic
This means that they contain an acid
Examples of everyday materials that contain acids are:
Lemons and other citric fruits as well as materials that contain these for example Orange crush
Vinegar (contains ethanoic/acetic acid)
Battery acid (sulphuric acid)
Other acids include: […]

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Experiment: investigating reversible reactions
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Experiment: investigating reversible reactions

Notes, O Level Science Notes, Ordinary Level Notes

Experiment: investigating reversible reactions

By garikaib|2025-02-12T09:19:15+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment: investigating reversible reactions

Aim: Investigating reversible reactions

Materials: boiling tube, test tubes, copper sulphate crystals,solid ammonium chloride, red litmus paper, blue litmus paper, dilute hydrochloric acid, sodium hydroxide solution, potassium chromate solution, tongs

Heating ammonium chloride. Image credit youtube.com